More specifically, the apparatus of the invention relates to a truck or vehicle especially suited for dock and warehouse use which embodies a self-propelled truck or vehicle including a movable platform carriage assembly actuatable for lifting movement in a vertical direction by means of a pair of oppositely disposed triple-stage mast assemblies. The lift carriage and mast assemblies are mounted on a chassis having a drive and multi-mode steering capability to enable the vehicle to be turned at an angle from 0.degree. to 90.degree. in either direction by operation from an operator's cab mounted on and for movement with the carriage lift platform assembly. The vehicle further incorporates a stabilizing torque bar assembly operably associated with the mast assemblies for automatically and synchronously leveling action on the lift platform carriage assembly during raising and lowering thereof.
Prior material handling or lift apparatus of a different type but generally related to the subject matter of the present invention are described, for example, in U.S. Pat. Nos. 2,816,675 and 3,414,487.